Pyloric stenosis Quiz: Ace Your Exams

A 3-week-old girl presents to the pediatrician’s office with new-onset post-prandial vomiting. She and her monozygotic twin sister were born via spontaneous vaginal delivery at 36 weeks without complications. Both twins received pertussis prophylaxis before discharge as their school-aged sibling at home was being treated for pertussis. Family history is significant for ulcerative colitis in their father and asthma in their sibling. Her mother reports that the patient has been afebrile without coughing or breathing difficulties at home. She has been exclusively breastfed since birth. However, over the last 1-2 days she has vomited after each feeding. Her mother reports that the vomit is white in color and is very forceful. She notes that the infant continues to want to feed despite recurrent emesis. Physical exam demonstrates dry mucous membranes and capillary refill in 4 seconds. Abdominal exam is unremarkable. Which of the following elements of this patient’s history is most likely associated with the current condition?